KR101129146B1 - Method for identification of biological pathogens and chemical contaminants in a gaseous space - Google Patents

Abstract

A method is provided for identifying contaminants in gas spaces. The method comprises: generating a wideband optical waveform; Shaping the optical waveform to match an expected waveform for known contaminants; And transmitting the shaped light waveform to unknown contaminants. Upon receipt of the reflected waveform from the unknown pollutant, it is determined whether the unknown pollutant is related to the known pollutant based on the reflected waveform.

Optical Waveforms, Contaminants, Pathogens, Shapes, Waveforms, Transmit, Reflection, Amplitude, Optical Receivers, Optical Transmitters, Detection and Identification

Description

METHOOD FOR IDENTIFICATION OF BIOLOGICAL PATHOGENS AND CHEMICAL CONTAMINANTS IN A GASEOUS SPACE}

FIELD OF THE INVENTION The present invention generally relates to methods for identifying contaminants in gas spaces and, more particularly, to the determination and identification of biological pathogens and chemical contaminants or to the presence of certain chemical species generated by tags. System and method.

Chemical and biological agents pose a real and unexpected threat to humanity. A wide variety of synthetic chemicals, toxins and biological materials have been developed for use as combat or terrorist agents. Some chemical and biological agents are readily available and can be readily prepared in large quantities. Rapid and accurate detection of chemical and biological agents at very low concentration levels is critical to successful defense against the use of such agents as inorganics.

In addition, chemical effluent from chemical processing manufacturing plants or factories, from a lack of fuel such as rocket propellants, or particularly from the volatility of chemical tags placed in drugs or explosives is far away or quite It needs to be detected sensitively in close proximity.

Since chemical and biological agents are effective in small doses, sensitivity is an important feature in any detection system. Complex and rapidly changing operating environments likewise require detection systems that exhibit high sensitivity. In other words, sensitivity is necessary to identify chemical and biological agents from other harmful substances present in the environment. Finally, the rate at which agents are identified is essential for determining the appropriate response to the threat environment. Speed is also an important feature in that the response of the complex agents can be found during the scan. Accordingly, it is desirable to provide a detection scheme that describes each of these technical challenges.

The description in this section merely provides the background associated with the present invention, and does not constitute a prior art.

A method of identifying contaminants in a gas space is provided. The method includes a method of identifying contaminants in a gas space, the method comprising: transmitting an initial wideband optical waveform to a known contaminant, receiving an initial wideband optical waveform that is spectrally reflected by the known contaminant, and a spectral reflected initial broadband Dividing an optical waveform into a plurality of optical waveforms having different frequency ranges, determining an expected waveform at each different frequency range, and determining a spectral response to known contaminants based on the expected waveforms. Generating an interrogating wideband optical waveform that is an ultra-continuous optical waveform, shaping the optical waveform to match an expected spectral waveform for known contaminants, and contaminants for which the shaped interrogating optical waveform is unknown. And receiving the reflected portion of the shaped question light waveform reflected by unknown contaminants. Step, and determining whether or not related with the question and not of the non-not on the basis of the reflected portion of the light wave type contaminants contaminants.

Further areas of applicability will become apparent from the description provided herein. It is to be understood that the foregoing description and specific embodiments are intended for purposes of illustration only and are not intended to limit the scope of the invention.

1 is a flow chart illustrating a method of identifying a biological pathogen,

2 is a block diagram of an exemplary system for detecting and identifying biological pathogens or chemical contaminants,

3 is a schematic of an exemplary light source that may be used in the detection system,

4 is a schematic of exemplary waveform shaping components that may be used in the detection system;

5A and 5B are block diagrams depicting exemplary detection schemes that may be used in the detection system.

The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

1 shows a method for identifying the presence of biological pathogens, chemical contaminants or chemical tags based on the principles of spectral detection. Before identifying unknown pathogens, a library of spectral reactions is collected for the pathogens of interest indicated in (12). In one exemplary embodiment, the spectroscopic response (ie, predicted waveform) for a given biological pathogen can be determined by transmitting a wideband optical waveform to a known biological pathogen of interest. The waveform reflected by the biological pathogen of interest is then captured as a spectral response for the biological pathogen and stored in the library. In order to improve the sensitivity and selectivity of the detection process, the light waveform reflected by the biological pathogen of interest can be divided into a plurality of spectral components (eg, waveforms with different frequency ranges). have. Spectral responses in each of the different spectral components are captured and stored in a library, thereby generating a series of expected waveforms for a given biological pathogen. This process is repeated for various other biological pathogens in order to generate the entire library.

To identify unknown biological pathogens, the wideband lightwaves are first shaped in step 14 to match the expected waveforms for known biological pathogens. Shaping is understood to mean adjusting the amplitude and / or phase of some or all of the spectral components of the waveform. By shaping the interrogating waveform to match the expected waveform, only light that is expected to exhibit a spectral response is transmitted to the target. In other words, light that will not be used in the detection process is not transmitted to the target object, thereby maximizing the signal-to-noise ratio of the reflected waveform. The orthopedic waveform is transmitted in step 16 towards an unknown biological pathogen, and the spectral response implemented in the reflected waveform is determined to determine whether the unknown biological pathogen correlates with a known biological pathogen ( 18). The unknown biological pathogen is identified when the spectral response of the reflected waveform matches the spectral response of the known biological pathogen.

Different waveforms or pulses of waveforms can be used to interrogate known biological pathogens. Each different waveform or pulse of waveform is shaped to match the expected waveform for known biological pathogens identified in the library, and then transmitted to unknown biological pathogens. In this way, unknown biological pathogens can be assessed with respect to each known pathogen. Although the following description is provided in connection with biological pathogens, it is readily understood that this technique is suitable for detecting and / or identifying chemical agents, toxins and other forms of contaminants that can be identified by gaseous volume. .

2 depicts an example system 20 for detecting and identifying biological pathogens. The detection system 20 generally consists of an optical transmitter 30, an optical receiver 50, a digital signal processor 22, and a library of spectral responses to known biological pathogens. The optical transmitter 30 includes a light source 32 and a waveform shaping component 34. The light receiver 50 includes a filtering component 52 and a photodetector 54. Each of these components is further described below.

The light source 32 produces a pulsed wideband optical waveform that operates at a giga-pulse repetition rate in the terahertz frequency range. Each pulse or series of pulses can be used to interrogate unknown contaminants. Operation at such high repetition rates increases the speed at which detection can occur, while the use of wideband terahertz waveforms improves the selectivity of the system as further described below.

In one exemplary embodiment, the optical waveform is further defined as a supercontinuum waveform (ie, a waveform with an ultra-wide spectral bandwidth generated by a nonlinear process). Ultracontinuous waveforms can be generated using various techniques. For example, supercontinuous waveforms can be generated by spectrally broadening (ie, increasing the number of spectral components) of an optical waveform by propagating it through some nonlinear media such as crystals. 3 shows one exemplary technique in which the light source 32 is implemented using a 10 gigahertz comb fixed, mode-locked laser 36 operatively connected to the nonlinear fiber 38. An optical amplifier 37 (eg, erbium-doped fiber amplifier) may be inserted between the laser 36 and the nonlinear fiber 38. It is contemplated that other forms of pulsed light sources (eg, fiber ring lasers) may be used. Likewise, other methods of broadening the light spectrum of a light waveform across a range of frequencies are contemplated by this disclosure. For example, a pulsed light source can be passed through other mediators causing self-phase modulation to broaden the spectrum of individual pulses. Alternatively, supercontinuous waveforms can be achieved using techniques such as Raman scattering or four-wave mixing.

4 depicts an exemplary embodiment of a waveform shaping component. In this embodiment, the wideband optical waveform is preferably shaped across different frequency ranges imparted to the waveform. Thus, light from the light source 32 is input to a demultiplexer 42. The demultiplexer 42 divides the wideband optical waveform into a plurality of optical waveforms that traverse different adjacent frequency ranges. It is readily understood that some waveforms are output by the demultiplexer 42 or a series of multiplexers. A plurality of optical modulators 44 are in turn coupled to the demultiplexer 42, each optical modulator receiving one of the optical waveforms output from the demultiplexer 42. Each of the optical modulators is further controlled by a signal processor 22 in data communication with a data store of expected waveforms. However, it is contemplated that the waveform can be shaped using a single light modulator.

In operation, light waveforms at different respective frequencies can be shaped by one of the light modulators according to the expected spectral response (ie, waveform) to the biological pathogen of interest. In other words, the optical waveform of the first frequency is modulated according to the expected spectral response at the first frequency, and the optical waveform of the second frequency is modulated according to the expected spectral response at the second frequency. The resulting waveforms are then input to a multiplexer 46 which recombines the waveforms into a single wideband optical waveform. In a less sophisticated approach, a wavelength blocker can be used in place of the optical modulators. Wavelengths that are expected to exhibit a spectral response pass while wavelengths that are not expected to exhibit a spectral response are completely blocked, thus being removed from the interrogating wavelengths. It is readily understood that other forms of shaping or filtering means may be used instead of light modulators.

In order to interrogate an unknown object purpose, each light pulse (or series of pulses) can be shaped in the manner described above to match the expected waveform for a known biological pathogen. In this way, unknown subjects can be compared to hundreds of thousands of known biological pathogens in a very short time. When unknown targets extend out of the field of view of the optical transmitter, the transmitter can be scanned to interrogate a larger target region. In this case, the interrogating waveform at each injection location will match a single biological pathogen until the entire target area is scanned. The interrogating waveform can then be matched to different biological pathogens and the target area can be re-injected. Alternatively, different light pulses can be matched to different biological pathogens at a given scanning position. Once the interrogating waveform is transmitted for biological pathogens of continuous interest, the optical transmitter can be moved to a different scanning position, and the process is repeated until the entire target area is scanned.

On the receiver side, an optical matched filter is preferably used to further improve the selectivity of the detection system. Noting the biological pathogen of interest, the light matching filter can be controlled by a signal processor to filter the reflected waveform according to the expected waveform for the biological pathogen. Although not limited to this, auto-correlating a reflected waveform entering the interrogating waveform is one exemplary filtering technique.

Different detection schemes can be used to analyze the reflected waveforms. In FIG. 5A, the reflected waveform is distributed by a splitter 62 into a plurality of divided waveforms of equal intensity. A plurality of light matching filters 64 are coupled to the light splitter 62 so that each light matching filter receives one of the waveforms output from the splitter 62. Each of the light matching filters 64 is further controlled by the signal processor 22. In this way, each waveform can be filtered at different frequencies. For example, the first waveform is filtered only to pass the expected spectral response at the first frequency, while the second waveform is filtered only to pass the expected spectral response at the second frequency. The filtered waveforms are then input to a signal combiner 66 which recombines the waveforms into a single waveform. Finally, a photodetector 68 operable over the entire spectral bandwidth of the interrogating waveform converts the waveform into an analog signal.

When the reflected waveforms from the target correlate to the expected waveforms, the matched filters pass the expected spectral response in the light receiving element, filtering out most of the noise. Conversely, when the targets are not related to the expected waveform, the matched filters filter most of the reflected waveform. Thus, threshold detection schemes of amplitudes can be used to determine whether or not the target objects are related to the expected biological pathogens. In one exemplary embodiment, the signal output from the light receiving element 68 is input to an analog to digital converter which in turn is coupled to a signal processor. The threshold detection scheme can be implemented in software and is performed by a signal processor in a manner known in the art.

In an alternative approach, detection is based on the evaluation of each frequency component of the reflected waveform as shown in FIG. 5B. In this approach, the reflected waveform is input to a demultiplexer 70 that divides the waveform into a plurality of waveforms having different frequencies. Each waveform is filtered again by one of the plurality of optical filters 72 according to the waveform expected at a predetermined frequency. However, each filtered waveform is input to a different light receiving element 74, so that post-processing signal analysis can be performed on each frequency component to determine whether the target correlates with the expected biological pathogen. . It is readily understood that other detection schemes may be included in the broad aspects of the present invention.

Claims (10)

As a method for identifying contaminants in gas spaces: Transmitting the initial broadband optical waveform to known contaminants, Receiving an initial wideband optical waveform that is spectrally reflected by the known contaminants, Dividing the spectral reflected initial broadband optical waveform into a plurality of optical waveforms having different frequency ranges; Determining an expected waveform in each of the different frequency ranges, Determining the spectral response to known contaminants based on the expected waveforms, Generating an interrogating wideband lightwave that is a supercontinuous lightwave, Shaping the light waveform to match the expected spectral waveform for known contaminants, Transmitting the structured question light waveform to unknown contaminants, Receiving a reflected portion of a shaped query lightwave reflected by unknown contaminants, and Determining whether the unknown pollutant is related to the known pollutant based on the reflected portion of the question light waveform. delete The method of claim 1, Shaping the interrogation light waveform further comprises adjusting at least one amplitude or phase of the interrogation light waveform. delete delete The method of claim 1, Shaping the interrogation light waveform further comprises simultaneously shaping the interrogation light waveform at a plurality of different frequencies. The method of claim 6, Shaping the interrogation light waveform further comprises blocking the interrogation light waveform at frequencies at which the expected waveform does not exhibit a spectral response. The method of claim 6, Shaping the interrogation light waveform further comprises optically modulating the interrogation light waveform at respective frequencies at which the expected waveform exhibits a spectral response. The method of claim 1, Receiving the shaped question light waveform further comprises filtering the shaped question light waveform based on an expected reflection waveform for the known pollutant. The method of claim 1, Receiving the shaped question light waveform further comprises automatically correlating the shaped question light waveform to an expected reflection waveform for the known pollutant.

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